The present invention relates generally to the field of medical devices, and more particularly to a medical device capable of identifying a hemodynamically unstable arrhythmia based upon signals obtained from an optical hemodynamic sensor.
Medical devices, both internal and external, have long been used to monitor cardiac activity to detect various types of cardiac arrhythmias and to select and provide an appropriate therapy based upon the type of arrhythmia detected. Conventionally, such cardiac arrhythmia detection has been based upon an analysis of one or both of the electrical and hemodynamic functioning of the heart.
Optical hemodynamic sensors, such as pulse oximeters, have been used in medical devices to obtain data indicative of the hemodynamic function of the heart, for instance, by determining blood oxygen saturation levels. Practical applications for optical hemodynamic sensors, however, have been limited because such sensors are highly susceptible to motion; that is, movement by the patient or of the sensor tends to introduce significant noise onto an output signal of the sensor.